板料冲压成型CAE中拉裂的预测研究及应用

将Hill集中性失稳理论和Swift分散性失稳理论应用到各向同性板料的失稳判定，将Marciniak和Kuczynski的凹槽损伤失稳理论应用到正交各向异性板料的失稳判定，对冲压成型中板料在不同时刻的稳定性进行数值化描述，并运用计算机仿真技术进行直观的表现来预测拉裂；将开发的仿真系统用于汽车翼子板冲压工艺分析，准确地预测了可能出现拉裂的部位．这对于模具开发中确定合理的冲压工艺方案，有效地防止拉裂的发生有重要的实用价值．

Prediction and Application of Fractures in CAE of Sheet Forming

The fracture of sheets is caused by the instability of loading. To determine whether materials are instable or not, Hill's totalized instability theory and Swift's diffusion instability theory, which are based on continuous mechanics, were applied to isotropic sheet. And Marciniak and Kuczynski's analysis was applied to orthotropic sheet,which introduced thickness imperfections normal to the principal stress and strain direction as a groove simulating preexisting defects in the material. The stability of each part of the sheet at each moment was described with numeric method, and the results were shown in computer simulation. The simulation system was applied to analyze the forming techniques of front fender,which can predict the fracture in sheet forming. This is of great practical value in industry for determining the suitable sheet forming technology and avoiding fractures.